Electrochemical cells (or batteries) are used in a variety of electronic devices as a power source. Manufacturers continually try to increase the capabilities and features of these electronic devices, which in turn increases the demands on the batteries used therein. However, the size and shape of the batteries used in the devices are limited, or fixed, by the battery compartment within the devices. As a result, if, for example, the discharge performance or physical performance (e.g., resistance to leakage or crush strength) of the cell is to be improved, such improvements must be achieved by making internal improvements or refinements within the cell.
Accordingly, to-date, solutions to provide increased performance of the cell have included, for example, making refinements to the physical components of the cell. For example, the dimensions or thicknesses of various cell components may be modified in order to minimize the internal cell volume taken up by the housing, the seal or vent, as well as reducing the thickness of the separator between the anode and cathode. Such solutions are an attempt to maximize the internal volume of the cell that is available for active material.
In addition to, or as an alternative to, the modifications made in the physical features of the cell in an attempt to improve cell performance, the composition of various cell components, such as the cathode material, electrolyte, and/or anode material, may be modified in an attempt to increase cell performance. However, it is also to be recognized that the electrochemical processes or reactions that occur within the cell result in an increase of cathode thickness upon discharge, and an accompanying formation of reaction products. Further, as the discharge depth of the cell increases, additional reaction products will be generated, causing incremental volume increases of discharge products that need to be accommodated by incorporation of sufficient void volume within the cell.
In view of the foregoing, it is to be recognized that each refinement in cell design that brings with it an improvement in cell performance also creates a challenge (e.g., refined cathode material composition that increases discharge performance, which in turn places greater demands on void volume due to the increase in reaction products). Accordingly, a continuing need exists for a cell design that effectively balances these demands—that is, a need continues to exist for an improved cell design that optimizes output or discharge performance, internal void volume, and other physical demands (e.g., crush strength).